1. Field of the Invention
The present invention relates to a test fixture, and more particularly to a test fixture and a method for testing a semi-finished chip package. The test fixture keeps the semi-finished chip package from deforming during the test method so that a chip or a circuit in the semi-finished chip package would not be damaged.
2. Description of Related Art
To keep a quality and a production rate of chip packages, finished chip-packages experience a final test. Moreover, semi-finished chip packages that are not encapsulated would experience an intermediate test to determine whether chips in the semi-finished chip packages function well or not.
With reference to FIGS. 7 and 8, a test system implements the intermediate test to semi-finished chip packages (90) un-encapsulated and having an outer edge and multiple contacts. The test system has a vacuum suction head (80) and a test fixture (70).
The vacuum suction head (80) may be connected to a vacuum pump and has an annular bottom edge and a through hole. The through hole is defined through the vacuum suction head (80) and communicates with the vacuum pump so a suction force from the operating vacuum pump passes through the through hole and holds one semi-finished chip package (90) on the annular bottom edge of the vacuum suction head (80).
The test fixture (70) is aligned and cooperates with the vacuum suction head (80) to test the semi-finished chip package (90) and has a top, a recess (71) and multiple probes (72). The recess (71) is defined in the top of the test fixture (70) and has an inner bottom surface. The probes (72) are conductive, are mounted through the test fixture (70), protrude up from the inner bottom surface of the recess (71) and are connected electrically to a testing device.
When test system implements the intermediate test, the vacuum suction head (80) provides a suction force and holds one semi-finished chip package (90) with the annular bottom edge abutting the outer edge of the semi-finished chip package (90). The vacuum suction head (80) then moves the semi-finished chip package (90) into the recess (71) and the annular bottom edge presses outer edge of the semi-finished chip package (90) to with a downward mechanical force. The contacts of the semi-finished chip package (90) respectively contact the probes (72) so that the testing device may test the semi-finished chip package (90) through the probes (72).
However, the annular bottom edge of the vacuum suction head (80) pressing the outer edge of the semi-finished chip package (90), the suction force sucking a central area of the semi-finished chip package (90) causes the semi-finished chip package (90) to be deform and curve. The deformation and curve of the semi-finished chip package (90) make a circuit or a chip on the semi-finished chip package (90) be damaged. Furthermore, semi-finished chip package (90) impacts the probes (72) without any cushions so that the probes (72) breaks easily.
To overcome the shortcomings, the present invention provides a test fixture and a method for testing a semi-finished chip package to mitigate or obviate the aforementioned problems.